This is a project which provides for a comprehensive approach to hormone action. The hormone emphasized is insulin, but studies also include insulin-like growth factors, steroid hormones and cyclic nucleotide. To accomplish our goal we have established three service cores. A radioligand assay core serves to iodinate hormones and other proteins, provides a number of insulin analogs, supplies cell membranes for raidoreceptor assay, a radioimmunoassay facility and a computer service. The tissue culture core prepares a number of different cell culture media and large volumes of cultured cells. The molecular biology core supplies reticulocyte lysates and SAC protein for mRNA assays, a faculty for the production and plasmid cloning of cDNA, and DNA sequencing. These cores are supported by an administrative facility and an enrichment program. Several pilot and feasibility studies in areas related to the theme of the Center are supported.